With all due respect, Mercy, much like us, doesn't know much about what's going on behind the scenes, aside from what he/she is told. That much is evident from the transmog thread. They are moderating and by default taking a stance that supports the current rules of the server, it's what's expected of them and there's nothing wrong with that. Don't take that quote as gospel though, the people actually in charge most certainly pay attention to the realm and will do what's best for them, and what's best for the realms seems to be shifting away from multiboxing being allowed.
I've been playing on Molten before Cata realms were even a twinkle in Kaer's eye, so I think I can safely say that the mboxxing situation has gotten worse than ever before and more and more people are getting fed up with it, something very well could happen at some point, making our voices heard is always good and thankfully these people that feel their unfair playstyle is threatened always come out of the woodwork when this thread pops up to cause it to get many pages of replies, making it even more likely for someone substantial to the development of the realm sees just how consistent and more widespread the discontent towards it is. Each post chips away at the foundation, if literal thousands of players started posting about how much it bothered them it would be gone within a week guaranteed.